The Synthesis of Poly(arylene ether)s in Solution at Pilot-Plant Scale with Control over Molecular Weight and End-Group Composition

The lab-scale optimization and pilot-plant-scale synthesis of a poly(aryl ether ketone) is reported. The polymer produced had the desired properties of low molecular weight (Mw = 14−15 kD, Mn = 6.3−6.5 kD), reasonable polydispersity (PD = 2.37−2.39), and well-defined controlled end groups. This has been accomplished using a one-step solution polymerization of 4,4'-difluorobenzophenone (DFBP), bisphenol A (BPA), and 4-tert-butylphenol (tBP). The presence or absence of a stoichiometric amount of tBP in the polymerization reaction dictated whether the obtained polymer possessed exclusively a halide or a tert-butylphenol terminus. Simple variation of the ratio of difluorobenzophenone to BPA controls the molecular weight of the obtained polymer without affecting the polydispersity. Several other factors were examined to completely optimize the polymerization process: the replacement of 4,4'-difluorobenzophenone with 4,4'-dichlorobenzophenone as a cost-saving measure, the effect of temperature, and the effect of the concentration of the reactants.